Lifting machine such as a crane



m 23, 1929. BERNHARD 1,722,125

LIFTING MACHINE SUCH AS CRANES Filed April 25, 1928 Patented July 23,1929.

snares g v 1,222,125 rarest rare.

JOI-IANN MARTIN BERNHARD, OF MAISING, NEAR MUNICH, GERMANY, ASSIGNOR TOA T G ALLGEMEINE TRANSPORTANLAGEN-GESELLSCHAFT li'I. E. ii, 0E LEIPZIG,GERMANY, A CORPORATION OF GER-MANY.

LIFTING MACHINE SUCH .AS A CRANE.

1 Application, filed April 23, 1928, Serial No.

Winch gears or winch gears which were hori- I V zontally displaceable onthe crane framework have hitherto been employed, which winch gears hadto be designed and dimensioned for the whole load to be raised andconsequently also necessitated the use of powerful driving motors.lVinches of this kind are equipped with driving gear, brakes, couplings,drums and controlling devices, which likewise have to be constructed tocorrespond to the full load which the motor has to carry. As consequenceof these facts, the said known machines must of necessity have alargetotal weight and consequently are very expensive in initial cost. If,now, the raising gear or the loading plant respectively is to beprovided with conveying means, such as, for instance, grabs, tippingvessels, grippers or the like, then expensive closing and emptying devies are necessary in addition, which renders the construction of thewhole winch gear considerably heavier. More-over, the attendance ofwinch gear of this kind necessitates the most careful attention on thepart of the crane driver, especially in the case of winch gear havingonly one motor, in which the carrying out of the control operations inthe wrong order may cause the falling down of the conveying means.

The idea of partly counter-balancing the load suspended from the craneby means of movably arranged counterweights is not new per seforinstance, in the construction of lifts it is universally customary tocounter balance the weight of the cage and half the maximum workingload. Nevertheless, in such cases, the upward and downward movements ofthe cage, and likewise the contrary movements of the counter-weight areproduced by means of a stationary winch gear.

According to the present invention the raising and lowering of the loadis efiected by means of a climbing crab adapted to move up and down inthe framework of the lifting machine and provided with a driving motorfor effecting the said movements, which crab can also be employed as apartial counter- 272, 2 01, and in Germany March 23, 192?.

weight for the load. The said motor drives chmbing pinions throughintermediary gear ing, which pinlons engage with rack bars or the likearranged on the framework of the lifting machine.

With a lifting machine of this kind, the load which is to be moved ispartly counterbalanced by the total weight of the motor driven climbingcrab, so that the total lifting work done on theload is in part effectedby means of the descending crab, and only the remaining amount has to bedone by the driving motor. As compared with lifting machines withstationary winches, the necessary motor output is very considerablydiminished by the employment of a climbing crab.

The weight of the climbing crab is made up of the individual weights ofthe crab framework, the driving motor together with the gearing andpossibly couplings and a winch drum which is necessary in particularcases.

The individual weight of such a climbing crab may be artificiallyincreased or diminished by the provision of additional weights orcounterweights.

A preferred constructional form of a crane according to the invention isillustrated diagrammatically by way of example in the accompanyingdrawings, in which Fig. 1 is a side elevation of the crane.

Fig. 2 is a plan of the lower part of the crane pillar,

Fig. 3is a detail showing the crab in front elevation,

Fig. 4 is a plan of Fig. 3, and

Fig. 5 is a side view of the crab and the supporting structure.

As can be seen from the drawings, theclimbing crab moves up and down inthe framework pl of the crane, supported by a pillar having three legs(Z. The said crab consists of a rigid frame in which the mechanicalparts such as the motor h, the rack pinions 7" and the gear 2' togetherwith the brakes a, m are arranged. The rack pinions f engage with rackbars g, which are fixed in any suitable manner to the framework cl ofthe crane or the like. The load such as the grab c is suspended fromropes or cables at, which pass over snatch blocks b and are connected toa drum is on the crab, which is driven by the motor it through gears 2'and Z.

The weight of the climbing crab may be artificially increased by meansof an additional weight 0.

The mode of operation of a plant of this kind provided with a climbingcrab is as follows:

The raising and lowering of the load is effected by downward and upwardmovement of the climbing crab respectively, the said crab being set inmotion by means of the motor h. If it is desired to raise or lower thegrab by the means of drum 7a, the crab is held stationary by the brakea, and the drum is driven by the motor it, through gears 2' and Z.

It now the grab is to be raised or lowered with the crab acting as acounterweight, the motor 70 is switched back from the driving gear ofthe drum on to the driving gear of the rack pinion f and the brake m isput into operation for the purpose of maintaining the drum isstationary. By releasing the brake n at the same time the rack pinion fwill then be driven by the motor h, and the crab will move upwards ordownwards respectively.

If the loading place is not at the same height as the unloading place,it'is preferable to'provide an indicating device showing the position ofthe crab at any given time, so that the crane driver is informed as tothe position of the crab and oi the goods to be conveyed.

I claim: J

1. In a lifting machine, such as a crane, for

' the raising and lowering of loads, the combination of a framework, agrab, a climbing crab adapted to move up and down in said framework andto act as a partial counterweight for the load to be raised, a wincharranged onrsaid crab adapted to move said grab up and down, drivingmeans on said crab adapted to move said crab up and down and to operatethe winch, a brake on the crab adapted to hold the winch when the crabis raised or lowered, and a second brake on the crab arranged torestrain movement of the:

crab when the winch is operated.

2. In a lifting machine, such as a crane, for the raising and loweringof loads, the combination of a framework, a grab, a climbing crabadapted to move up and down in said frame work and'to act as a partialcounterweight for the load to be raised, a winch arranged on said crabadapted to move said grab up and down, driving means on said crab,coupling means on the crab adapted to couple said driving means so as tomove said crab up and down, couplin means on the crab'adapted to couplesaid driving means with said winch, a brake on the crab adapted to holdthe Winch when the crab is raised or lowered, and a second brake on thecrab arranged to restrain movement of the crab when the Winch isoperated.

Signed at Munich, Germany, this 2nd day of April, 1928.

J OH. MARTIN BERNI-IARD.

